Filter

ABSTRACT

A filter is provided for beverage machines such as coffee machines. The filter material is a layer of woven or molded polymeric plastic having a mesh size of between about 52 and 70 microns. Filter material is supported by a coarse support grid which in turn is supported by a carrier.

United States Patent Schollhamer 1 Mar. 28, 1972 [54] FILTER 3,348,69510/1967 Rosaen ..210/499 X 3,382,305 5/1968 [72] Inventor. George R.Schollhamer, Ph1ladelph1a, Pa. 3,500,991 M1970 [73] Assignee:Rudd-Melikian, Inc., Warminster, Bucks 3,496,861 2/ 1970 Stahler..99/289 Count Pa.

y FOREIGN PATENTS OR APPLICATIONS [22] Filed: Mar. 11, 1970 1,157,19711/1963 Germany ..210/479 1 p NM 18,570 502,911 12/1954 Italy ..210/495[52] 11.8. C1 ..210/474, 210/478, 210/479, 210/489, 210/495, 210/499[51] Int. ('1 B0ld 25/04 [5 8] Field of Search ..210/479, 480, 499, 474,478, 210/495, 489; 99/289, 297, 300; 16l/DIG. 5

[56] References Cited UNITED STATES PATENTS 3,165,473 1/1965 Pall et a1...210/493 X 3,206,031 9/1965 Messa ...2l0/479 X Royer et a1 ..210/493 XPrimary Examiner-Samih N. Zaharna Assistant Examiner-Frederick F.Calvetti Attorney-Seidel, Gonda and Goldharnmer [57] ABSTRACT A filteris provided for beverage machines such as coffee machinesv The filtermaterial is a layer of woven or molded polymeric plastic having a meshsize of between about 52 and 70 microns. Filter material is supported bya coarse support grid which in turn is supported by a carrier.

3 Claims, 4 Drawing Figures PATENTEDmze 1912 3,651.94?

Inn/51v TOR swam-x5010; um MEI? FILTER This invention relates to afilter particularly designed for use in beverage machines which havegrounds and fines which are to be separated from a beverage as, forexample, a coffee machine.

Many commercial coin operated coffee vending machines utilize freshground coffee and dispense freshly brewed single cup quantities ofcoffee upon demand. It is important that the brewed coffee besubstantially free of fines. Fines not only leave an unattractiveresidue at the bottom of each cup of coffee but also render the bottomportion of each cup unpalatable.

It has been suggested that individual sheets of filter paper be used inbrewing each cup of coffee. However, this has been unacceptable becauseof the expense thereof and because of the complexity of the mechanismfor feeding and removing the individual sheet of filter paper.

It has also been suggested that a stainless steel electro etched filterbe utilized. This has proven generally satisfactory. However, thestainless steel filter is expensive and must be cleaned periodically.

It has been further suggested that a nylon filter be used in combinationwith a stainless steel electro-etched filter. However, the expense ofthe electro-etched filter is not eliminated and the fines tended to clogthe combined nylon and stainless steel filters.

It is an object of the present invention to provide a filter whichovercomes the deficiencies of prior art filters.

It is another object of the present invention to provide a novel filterfor beverage machines.

It is another object of the present invention to provide an expendablefilter which can be manufactured inexpensively and the discarded afterone or more uses.

It is another object of the present invention to provide a novelexpendable filter for filtering out fines within an acceptable level foruse in coffee machines.

Other objects will appear hereinafter.

The above and other objects are accomplished by providing the filter ofthe present invention. The filter is structurally interrelated in amanner so as to separate coffee grounds from the coffee beverage. Thefilter is structurally interelated in a manner whereby it may be madeinexpensively so as to be disposable after one or more uses.

The filter material is a woven polymeric material such as nylon orpolyester having a mesh size of about 52 to 70 microns. l have foundthat openings smaller than 52 micron mesh size will result in cloggingoffilter material l have found that openings greater than 70 micron meshsize result in fines flowing through the filter in an amount which isabove the acceptable level. The filter material may be supported by adiscrete support grid which may include a mesh woven screen of stainlesssteel wire or the like. Alternatively, the support grid may be formedintegrally in the carrier.

For the purpose of illustrating the invention, there is shown in thedrawings a form which is presently preferred; it being understood.however, that this invention is not limited to the precise arrangementsand instrumentalities shown.

FIG. 1 is a perspective view of a filter in accordance with the presentinvention.

FIG. 2 is a sectional view taken along the line 22 in FIG. 1.

FIG. 3 is a partial plan view ofthe filter of FIG. 1.

FIG. 4 is a sectional view similar to FIG. 2, but illustrating anotherembodiment of the present invention.

Referring to the drawings in detail, wherein like numerals indicate likeelements throughout the several view there is shown in FIG. 1 a filterin accordance with the present invention designated generally as 10. Thefilter includes a carrier 12 of any desired configuration. Asillustrated, the carrier 12 is generally rectangular and made from alightweight in expensive material such as a polymeric plastic. Thecarrier 12 may be constructed in any convenient manner but preferably isinjection molded.

The carrier 12 is provided with mounting means for securring it inproper position in a coffee beverage machine. The mounting means, asillustrated, includes a pair of downwardly depending legs 14 and 18 onopposite sides of the carrier. Leg 14 is provided with a latchingsurface 16. Leg 18 is provided with a corresponding latching surface 20.Other mounting means may be provided as desired.

The carrier 12 is provided with a generally rectangular shapedperipheral groove 21. A sealing ring 22 having a generally rectangularcross section is composed of a resilient material such as rubber orplastic and is force-fitted in the groove 21. The height of the ring 22is such that it its upper surface projects slightly beyond the top wall15 of the carrier 12 as will be apparent from FIG. 2. A centrallydisposed planar support surface 24 is provided having a downwardlydepending skirt 26 Support surface 24 is circular in configuration andof a size so that the skirt 26 provides the inner peripheral wall forthe groove 21. The remainder of the groove is defined by bottom wall 25and outer peripheral wall 27.

The support surface 24 has a plurality of holes substantially uniform insize therein to form a grid. The surface 24 has preferably theappearance and dimensions of a woven mesh screen which is relativelycoarse. The purpose of the surface 24 is to provide the necessarysupport for a layer of filter material 28. In a conventional coffeemachine, pressures utilized to force the water through the coffee grindsare in the range of 7 to 14 p.s.i. and are commonly in the nature of 10p.s.i. l have found that the operation of the filter is unsatisfactoryunless the layer of filter material 28 is supported by the mesh support24.

The layer of filter material 28 is preferably a polymeric plastic wovenfabric material such as a fabric of polyester or a polyamide. A suitablepolyamide would be nylon and a suitable polyester would be Dacron. Thelayer of filter material 28 has a mesh screen size of between 52 andmicrons. l have found that openings smaller than 52 micron mesh sizeresult in the filter being clogged by the fines. I have found thatopenings greater than 70 micron mesh size result in fines passingthrough the filter in an amount which is above the acceptable level incommercial coffee machines.

The layer of filter material 28 may be molded or woven so long as thecritical micron size is attained. When the filter material 28 is madefrom nylon, it has a tendency to stain. l have found that polyestermaterials are less likely to stain when subjected to coffee. Both ofthese materials do not absorb heat rapidly, are not affected by thetemperature of the coffee, and do not get sticky or oily during use.

The filter 10 is easily assembled and utilizes a minimum number ofcomponents. The filter material 28 and carrier 12 may be consideredexpendable and disposed of after one or more uses. Alternatively, thelater of filter material 28 may be discarded after one or more useswhile retaining the other elements. The layer of filter material 28 isremovably secured to the carrier 12 and stretched taut over the surface24. The ring 22 is placed over the filter material 28 which ispreferably circular in configuration and of a diameter slightly greaterthan the diameter of the surface 24. The ring 22 locks the filtermaterial 28 into place over the surface 24. The surface 24 preventsdamaging distortion of the filter material 28 as the hot liquid passestherethrough. FIG. 3 is illustrative of surface 24 and the holes shownare larger and greater in number than actually utilized in surface 24.Surface 24 may be provided with the dimensions of an 18 X 18 meshscreen.

The filter material may be discarded after a desired number of 'uses.The ring 22 is merely removed from the groove 21 thus releasing thefilter material 28. A plurality of holes 23 may be provided in thebottom wall 25 of the groove 21 to facilitate release of the ring 22.The used filter material 28 may be discarded and a new piece snap-fitinto operative position.

It is deemed readily apparent that the filter of this invention is veryeconomical to use. It has been found that the material 28 can last for asubstantial number of cycles and need not be frequently changed.Furthermore, the material 28 is only material which need be discarded.Since the material 28 is relatively inexpensive, substantial savings maybe effected by use of the filter of the present invention while asuperior cup of coffee is produced.

ln HO. 4, there is illustrated another embodiment of the filter of thepresent invention designated generally as 10' The filter 10' isidentical with the filter 10 except as will be pointed out hereinafter.Accordingly, corresponding primed numerals are provided in FIG. 4 oncorresponding structure as shown in FIG. 1-3.

In FIG. 4, the lower peripheral edge of the carrier 12' is provided witha horizontally disposed, inwardly extending flange 32 terminating at itsinner end in an upwardly extending wall 26'. Flange 32 is slightly widerthan wall 25 for a purpose which will be made clear hereinafter. Thecarrier 12 includes a centrally-disposed bore 40. Wall 26 has a heightwhich is less than the height of the carrier 12'. A screen 36 is used inplace of the grid support surface 24. The screen 36 may be used as aninsert when molding the carrier 12' so that the skirt 38 thereof isintegrally secured to and forms a part of the wall 26'. Alternatively,the skirt 38 of the screen 36 may frictionally engage the wall 26', Thescreen 36 is preferably an l8 l8 mesh screen woven from stainless steelwire having a diameter of0.017 inches.

Thefiange 32 and wall 26' containing the skirt 38 cooperate with theremainder of the carrier to define annular groove 42. Annular groove 42is slightly wider than corresponding groove 21 in order to accommodateskirt 38 of screen 36. The layer 28 is sufficiently large so as tooverlie the screen 36 and extend radially outwardly therefrom. The ring22' is force-fitted into the annular channel 42 and causes the outerperipheral portion of the layer 28' to extend'downwardly into theannular channel 42 and overlie the upper surface of the flange 32. Thelayer 28' is thereby stretched taut over the bore 40 and screen 36.

The embodiment 10' is otherwise identical with the embodiment shown inFIGS. 1 and 2. The filter l facilitates rendering only the layer offilter material 28 disposable while retaining all of the other elements.When it is desired to discard the layer of filter material 28', thefirst step is to pry up the ring 22'. One or more holes 23' may beprovided in the flange 32 to facilitate pushing the ring 22' upwardly.Thereafter, the

layer 28 is discarded and a new one substituted in its place, In

the filter it will be noted that the screen 24' remains as an integralpart of the carrier.

The present invention has the advantage of materially reducing the costof replacing filters while at the same time results in an inexpensivefilter which will suprisingly filter out fines within an acceptablelevel commercially. The filters cost about percent of the cost offilters previously used. Also it is surprising that a woven flimslypolymeric plastic material which is 0.002 to 0.004 inches thick could beused for this purpose so long as the critical mesh size is adhered toand is supported by the mesh screen support. In use, the direction offlow of the liquid is downwardly in FIG. 2. In the embodiment oFIG. 4,the carrier is generally flat with the size of the bore 40 being about 2inches in diameter.

The present invention may be embodied in of the specific forms withoutdeparting from the spirit or essential attributes thereof and,accordingly, reference should be. made to the appended claims, ratherthan to the foregoing specification as indicating the scope of theinvention.

l claim:

1. A filter for use in a hot beverage making machine of the type wherethe hot beverage has grounds and fines which must be separated from thehot beverage comprising a carrier; means for mounting said carrier tosuch hot beverage making machine, said mounting means comprising atleast two downwardly depending legs on opposite sides of said carrier,each of said legs being provided with a latching surface of enfiagementwith such beverage making machine; said carrier avmg a substantiallyplanar central portion through which such hot beverage may pass, saidsubstantially planar central portion comprising a support surface with aplurality of holes therethrough; a peripheral groove formed in saidcarrier around said central portion, said peripheral groove comprisingan inner peripheral wall adjacent said central portion, a bottom walldisplaced from the plane of said central portion and an outer peripheralwall; a peripheral top wall disposed between said outer peripheral walland the peripheral wall of the carrier said carrier; a layer of filtermaterial overlying said support surface and extending into saidperipheral groove, said layer of filter material comprising a porousfabric material selected from the group consisting of essentiallypolyesters and polyamides having a thickness of about 0.002 to about0.004 inches and having openings of a mesh size of between about 52 and70 microns so that a substantial portion of the particulate grinds andfines in a hot beverage can be filtered; said central portion havingsufficient rigidity to restrain said layer of filter material from beingforced downwardly through said central portion by such hot beverage whensuch hot beverage is at a pressure in the range of about 7 to 14 poundsper square inch; a sealing ring, said sealing ring being comprised ofresilient material and having at least an upper surface, said sealingring being disposed in said peripheral groove with said upper surfaceprojecting slightly above said top wall, said sealing ring being inforce fitting relation with said peripheral walls of said groove, and acircumferential portion of said layer of filter material is disposedbetween said inner peripheral wall and said sealing ring to constrainsaid layer of filter material against movement.

2. A filter as defined in claim 1 wherein said support surface is formedintegrally with said carrier and comprises a plurality of holes ofsubstantially uniform size, and said support surface is relativelycoarse and corresponding to the appearance of a woven mesh screen.

3. A filter as defined in claim 1 wherein said first peripheral innerwall terminates below the plane of said peripheral top wall, saidsupport surface comprising a screen, said screen being 18X18 mesh beingwoven from stainless steel wire having a diameter of about 0.017 inches,said screen underlying said layer of filter material in supportingrelation thereto, a circumferential portion of said screen overlyingsaid inner peripheral wall and being disposed between saidcircumferential portion of said layer of filter material and said innerwall so that said sealing ring constrains said screen in contact withsaid layer of filter material.

2. A filter as defined in claim 1 wherein said support surface is formedintegrally with said carrier and comprises a plurality of holes ofsubstantially uniform size, and said support surface is relativelycoarse and corresponding to the appearance of a woven mesh screen.
 3. Afilter as defined in claim 1 wherein said first peripheral inner wallterminates below the plane of said peripheral top wall, said supportsurface comprising a screen, said screen being 18 X 18 mesh and beingwoven from stainless steel wire having a diameter of about 0.017 inches,said screen underlying said layer of filter mateiral in supportingrelation thereto, a circumferential portion of said screen overlyingsaid inner peripheral wall and being disposed between saidcircumferential portion of said layer of filter material and said innerwall so that said sealing ring constrains said screen in contact withsaid layer of filter material.